I used to use Avast Internet Security Suite, including their VPN. I left them recently, and chose to test the Mozilla VPN as a replacement. So far, not bad. But one thing the Avast mobile app featured that I think would be useful was that it could activate and de-activate itself, based on which network I was connected to.
Thus, when on my home network, which I trust, my phone doesn't use the VPN (and therefore incur any delays in data transmission), and when I leave the house, it automatically activates so I'm safe on public networks, and mobile data.
Can that be engineered into the Mozilla VPN app?
HTH.